"The single-responsibility principle (SRP) is a computer-programming principle that states that every module or class[1] should have responsibility over a single part of the functionality"
Такое определение гавно на самом деле и не раскрывает основного посыла, там если в вики дальше прочитать - то
Martin defines a responsibility as a reason to change, and concludes that a class or module should have one, and only one, the reason to be changed (